Mac OS X 10.6.3: Firefox Slowness, Random Delays

Several users have reported intermittent delays and overall slowness in Firefox after the Mac OS X 10.6.3 update. As described by Apple Discussions poster JamesFabin:

“I updated to 10.6.3 on my Mac Pro and suddenly firefox freezes for a second or more randomly…very often (3 times so far while typing this post). It happens on any action – scrolling, searching, right clicking. I do not see any issues in Safari – it acts normally. I’m running the latest version of Firefox, have plenty of memory (12 gigs), plenty of fast CPUs, no other software running except Firefox. It just started right after the system did the update and rebooted.”

Possible Solutions

Reset Firefox. Backup your Firefox profile (per these instructions), then quit Firefox if it is open. Start Firefox in safe mode by holding down the option key as you launch the program. When the Firefox Safe Mode dialog box appears, check all of the boxes to reset all settings and other information. Restore your Firefox profile via these instructions. Add back any toolbars or add-ons you had previously installed, one by one. If the delay issue resurfaces after a specific add-on, you’ve identified the culprit.

Mouse/keyboard freeze issues. Note that this issue may be conflated with another system-wide problem in which mouse/keyboard input intermittently stalls after the Mac OS X 10.6.3 update. See our previous coverage for potential fixes.